Engineering & Construction
Rebar Quantity Estimator
Estimate reinforcement quantity for a slab, a beam or a column, or from a known number of bars. Weights use 7850 kg/m³. This is a planning figure, not a bar bending schedule.
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How to estimate rebar quantity
- 1Pick a member. A slab uses spacing in both directions. A beam or column adds ties.
- 2Enter cover, diameters and spacing in millimetres. Bar length for a slab is the span minus cover at each end.
- 3Add a wastage percentage if you want an order allowance, then read the length and weight.
Questions
How is the number of bars calculated?
Count = floor((span − 2 × cover) / spacing) + 1. Spacing is centre to centre. The first and last bars sit at the cover, not half a space in from a theoretical grid.
How long is a tie?
The cut length is twice the sum of the inner width and inner depth, plus 24 bar diameters for two hooks. Cranked bars, laps and special hooks from the drawings are not included.